refactor: remove duplicated artifact deletion handler

[chlins]

Remove the duplicated artifact deletion event handler and enhance the internal artifact onDelete method.

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Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

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• Well Written Title and Summary of the PR
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[codecov]

Codecov Report

Merging #18959 (6e9d0d2) into main (26f6197) will decrease coverage by 0.01%.
The diff coverage is 62.50%.

@@            Coverage Diff             @@
##             main   #18959      +/-   ##
==========================================
- Coverage   67.42%   67.41%   -0.01%     
==========================================
  Files         993      992       -1     
  Lines      108772   108751      -21     
  Branches     2747     2747              
==========================================
- Hits        73341    73319      -22     
+ Misses      31502    31501       -1     
- Partials     3929     3931       +2     

Flag	Coverage Δ
unittests	67.41% <62.50%> (-0.01%)	⬇️

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Impacted Files	Coverage Δ
src/controller/event/handler/internal/artifact.go	75.70% <62.50%> (+0.70%)	⬆️

... and 10 files with indirect coverage changes

[wy65701436]

lgtm